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Document embassy::util::signal & embassy::util

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This commit is contained in:
Joshua Salzedo 2021-03-24 13:19:05 -07:00
parent 62009150bd
commit 40617fea04
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GPG Key ID: C3D0EB484493B731
2 changed files with 7 additions and 1 deletions
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1
embassy/src/util/mod.rs
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@ -1,3 +1,4 @@
//! Async utilities
mod drop_bomb; mod drop_bomb;
mod forever; mod forever;
mod mutex; mod mutex;

7
embassy/src/util/signal.rs
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@ -10,6 +10,9 @@ use crate::executor;
use crate::fmt::panic; use crate::fmt::panic;
use crate::interrupt::{Interrupt, InterruptExt}; use crate::interrupt::{Interrupt, InterruptExt};
/// Synchronization primitive. Allows creating awaitable signals that may be passed between tasks.
///
/// For more advanced use cases, please consider [futures-intrusive](https://crates.io/crates/futures-intrusive) channels or mutexes.
pub struct Signal<T> { pub struct Signal<T> {
state: UnsafeCell<State<T>>, state: UnsafeCell<State<T>>,
} }
@ -29,7 +32,7 @@ impl<T: Send> Signal<T> {
state: UnsafeCell::new(State::None), state: UnsafeCell::new(State::None),
} }
} }
/// Mark this Signal as completed.
pub fn signal(&self, val: T) { pub fn signal(&self, val: T) {
cortex_m::interrupt::free(|_| unsafe { cortex_m::interrupt::free(|_| unsafe {
let state = &mut *self.state.get(); let state = &mut *self.state.get();
@ -64,10 +67,12 @@ impl<T: Send> Signal<T> {
}) })
} }
/// Future that completes when this Signal has been signaled.
pub fn wait(&self) -> impl Future<Output = T> + '_ { pub fn wait(&self) -> impl Future<Output = T> + '_ {
futures::future::poll_fn(move |cx| self.poll_wait(cx)) futures::future::poll_fn(move |cx| self.poll_wait(cx))
} }
/// non-blocking method to check whether this signal has been signaled.
pub fn signaled(&self) -> bool { pub fn signaled(&self) -> bool {
cortex_m::interrupt::free(|_| matches!(unsafe { &*self.state.get() }, State::Signaled(_))) cortex_m::interrupt::free(|_| matches!(unsafe { &*self.state.get() }, State::Signaled(_)))
} }